Catalytic cracking catalyst compositions and processes for cracking hydrocarbons to maximize light olefins production are disclosed. Catalyst compositions comprise at least one zeolite having catalytic cracking activity under catalytic cracking conditions, preferably Y-type zeolite, which zeolite has low amounts of yttrium in specified ratios to rare earth metals exchanged on the zeolite. Catalyst and processes of the invention provide increased yields of light olefins and gasoline olefins during a FCC process as compared to conventional lanthanum containing Y-type zeolite FCC catalysts.